Process of making tungsten alloys



Feb; 7, 1933.

H. PETERSSON PROCESS OF MAKING TUNGSTEN ALLOYS vFiled Aug. 5, 1929 E M1 41 4o I 33 19 37 Il lll]v N k Sr 18 1: E* 535: /ecl ae 5E /E, ,H35 13, :E5/VAS :E EE k/ n n739:: 14 E67 f W36@ 46 i5 i /l/ M??? 20 5 i375 f a1 so; I N si 5l 1 I E: 18 2 I l wm Fifi 59 FIGLS INVENTOR HARRY PETERSSON f *SLE/35 y MwaX/ ATTORN Patented Feb. I7, 1933 vUNITED STATES PATENT OFFICE H ARY PETERBSON, OF MONTREAL, QUEBEC, CANADA, ASSIGNOB, MESNE ASSIGN- MENTS, TO PETEBSSON ALLOYB LIIITEILOI IOTBEAL, QUEBEC, CANADA, A COB- POBATION F QUEBEC PROCESS Ol' m6 TUNGSTEN ALLOYS Application Hed August l, 1929. Serial lo. 888,570.

bide and small quantities of metals such as tantalum, vanadium and the like, and the object er the invention is to provide a simple and inexpensive method for casting such metal alloys to obtain a homogeneous product,

which may be used for industrial purposes,

yso

such as cutting tools and the like.

Another object is to provide an apparatus in which the alloy charge is melted, thoroughly mixed and then cast without removing said charge from the apparatus.

Many suggestions have been made to use tuno'sten-carbide for industrial purposes, but diiiiculty has been encountered in obiing a homogeneous product moulded in any desirable form or shape because of the high temperatures which have to be used and the relatibn between the carbon and the tungsten at these temperatures. It is known that pure tungsten has a very high melting point about 33000 C. so that by producing its carbide in such a shape that it can be used for tec-i purposes, very high temperatures must be used thereby producing either a sint/ered or a melted product.

The only erueible` material. which is able stand these high temperatures is carbon, but tungsten absorbs a comparatively large quantity of carbon in liquid'form at these high temperatures, so that-the finished prodf uct is not homogeneous and is brittle.

To overcome the above diliculties, my procecnsists of removing the surplus free carbon from the mix and at the same time subjecting mix to a mechanical mixing move-l me nt.

4Recording to my invention, l provide an tri/cal furnace having spaced metal elec- Lf connected by a carbon resistance. lidably and rotatably mounted within the ."csistance or heating element is the Crucible hichis made of carbon. This carbon cruc ble is divided into two chambers, a mould chamber and a charge chamber separated from one another by a carbon wall, having a plugged orifice. Suitable cooling chambers surround the electrodes and the wall of the heating element.

I make use of the foregoing ap aratus in my improved process of making a omogeneous tungsten-carbide alloy. My process consists in placing the charge in the charging chamber when in its horizontal position and heating the said charge to a tem rature two or three hundred degrees below t e melting int of the tungsten. While the charge is cmg heated, the carbon Crucible is rotated. When the charge has reached this temperature of twoto three hundred degrees below its melting point the Crucible is swung into a vertical position and then subjected to a mechanical l:shaking movement. While the charge is being shaken the temperature of the charge is raised to its meltin point. Before the charge begins to melt an during the shaking action, a quantity of high metal oxides, pure metal, or both, is added to the charge. The liberated oxygen absorbs carbon from the charge and the carbon tube, as carbon oxide. The oxides hold the ercent of carbon within certain limits so t at the finished product contains no free carbon or a very small percentage of same. The shaking ensures that the charge is thoroughly mixed and is homogeneous. The plug between the chambers is removed and the tungsten alloy allowed to ow into the mould contained in the mould chamber.

In the accompanying drawing which shows my preferred form of furnace for making tungsten alloys,

Figure 1 is a side elevation of my improved furnace shown artly in section and in the horizontal position, with the water cooling jacket removed.

Figure 2 is a side elevation of my improved furnacev shown partly in section and in the vertical position, with the shaker mechanism attached thereto.

Figure 3 is a view of one type of the eccentric for controlling the movement of the shaker mechanism.

Referring more particularl to the drawing, 11 designates supporting rackets ada ted to receive the pivot extensions 12 of t e outer shell 13 of the furnace. This outer 2 Leaders shell 13 of the furnace has an annular space 14 therein for a cooling agent.

the casing. Suitable electrodes 18 are fitted in the upper and lower ends of the lined shell 13, each electrode being provided with an internal chamber 19 to which a cooling fluid is supplied from a source (not shown). It will be noted that'the adjacent ends of the electrodes are dished to receive the ends of the graphite heating element 2O to hold it in place. Ground carbon is placed between the graphite element and the inner surface of the lining ot'the shell. The heating element has a central bore'21 adapted to receive the carbon Crucible 22, which is divided into a charging chamber 23 and a moulder chamber 24 by the partition or'wall Q5. rl`he mould chamber has moulds 26 of any desired shape formed therein communicating with a channel 27 through the apertures 28. This'channel extends upwardly through the wall and a suitable plug E29 is placed in said channel to hold the charge in the charging chamber until it is desired to release same. The lower end 30 of the crucible is adapted to rest on a suitable bearing 31 during the tilting movement of the furnace. The up'per end 32 of the crueible isf connected to a sleeve 33 30 which extends upwardly through the top electrode and is provided with a groove 34. The electrodes are connected to a source of electrical supply shown diavrammatically as a transformer 35. A switch 3G may be placed 35 in the circuit to the transformer. The electrodes are held in place by any suitable end members 37 and 38 and insulation 39 is provided between the electrodes and the end members. Fitting into the groove at the top 40 of Ithe sleeve .33 is a removable collar 40 mounted within a bracket 41 secured to the end of a rod 42. the other end of which is pivotally secured to an eccentric rod 43. The ccentric 44 'is mounted on a shaft 45 rotata- 45 bly secured in suitable bearings and is of the adjustable type so that the throw of eccentricity may be quickly and conveniently altered to suit the desired movement of the Crucible. A typical adjustable eccentric is shown in Figures 2 and 3. lt will be seen that the eccentric ring is rotatably mounted in a sleeve member 46 .secured to the shaft by bolts 47.v These bolts are threaded through the shaft and a spring 48 is placed around each bolt and between the shaft and the inner wall of the sleeve. By moving the bolt. the eccentrieity of the sleeve is controlled and the movement of the eccentric ring with respect to the shaft is thus controlled. The rod 42 moves through suitable guides 49 and 50. In my method of castingtungsten alloys, the frucible is disconnected Jfrom the shaking or eccentric mechanism and is swung into the horizontal position shown in Figure 1. Into the charging chamber ot the crucible is A lining 15P.: of irebrick is'provided on the inner wall of turned on its pivots to the vertical posi placed the charge 51 of pure tungsten powffderor this powder mixed with tungsten-anhydride VOS. At a certain temperature the tungstenlanhydride is reduced to metal by taking Lup carbon lfrom the carbon tube or Crucible and after the tungsten-anhydride is reduced to a metal the carbonizing oit the pure metal will take place increasing with the temperature. To procure a homogeneous carbon-containing charge, the Crucible is revolved during the heating operation while in the horizontal position. This revolution vo't-the crucible may be conveniently accomplished by attaching a crank 33a: or any other suitable handle means to the sleeve 33. 8@ The furnace remains in the horizontal position as shown in Figure 1 until a temperature of some hundred degrees below the melting of the charge is attained. lhen this temperature has been reached the furnace is tn shown in Figure 2 and the Crucible raiseo'. and attached to the connecting rod. T crucible is shaken rapidly by means of tne eccentric. lVhile the charge is being shale the temperature is aised to the melting po At these temperatures, the tungsten abs comparatively large quantities of carbo which by re-crystallization partially crystallize as free carbon and so the product brittle. To prevent termined quantity of' high m mixed withthe charge betere the 1^ eration is perormed. The libera is discharged' as carbon oxide t' i certain percentage of the carbon from harge. lfilhen the reduction of oxides finished7 the partition is pierced molten charge is shaken into the mou The metal alloy delivered from the chargi chamber into the moulds is homogeneous is dense and possesses an almost negligible quantityot free carbon.

rhe current is shut olif during the casting operation or some time before pouring.

The device is very simple in operation and provides means which may be employed rmy improved method of obtaining a d homogeneous tungsten alloy without remoring the charge from the device, there ay reducing the cost of obtaining such alloys te a minimum.

The description has been directed to the process ot casting tungsten alloys. but it w be readily understood that other metal aiiovs ma)T be made by the same process without t parting from the spirit of the invention. must also be understood that metall oxides. or pure metal, or both. may be added to the charge during the shaking action dependi upon the characteristics of the materia.. which it is desired to cast. y

Having thus described my invention,

l claim is:

1. A method of making tungsten alloys 133 which consists in placing a tungsten mixture in a charging chamber, subjecting the charging chamber to a violent shaking action and heating the mixture to its melting temperature while retaining said mixture in the charging chamber and then causing the molten alloy to How into receiving moulds While continuing the shaking action.

2. A method of making tungsten alloys which consists in placing a tungsten mixture in a charging chamber, initially heatin the mixture to a temperature below its me ting point, subjecting the mixture to a violent shaking action while increasing the temperature thereof to the melting point and then causing the molten alloy to flow into receiving moulds while continuing the shaking action.

3. vA method of making tungsten alloys which consists in placing a tungsten mixture in a carbon retort, initially heating said mixture to a temperature below its melting point, increasing the temperature of the mixture to the melting point and simultaneously Subj ectingthe mixture to a violent shaking action',

adding a quantity of high metal oxides during the melting of the mixture and while continuing the shaking action and finally causing the molten alloy to How from the charging chamber into receiving moulds while continuing the aforesaid shaking action.

4. A method of making tungsten alloys which consists in placing a tungsten mixture in a carbon retort, rotating said retort while heating the mixture to a temperature below its melting point, then discontinuing the rotation of the retort and subjecting same to a violent shaking action while increasing the temperature` of the mixture to the melting point, adding a quantity of metal oxides to the mixture during fusing thereof and while the mixture is still retained in the charging chamber and then causing the molten alloy to How into receiving moulds while continuing the shaking actlon.

5. A method of making tungsten alloys which consists in placing a tungsten mixture in a carbon retort, heating the mixture to the melting point while subjecting the retort to a violent shaking action, adding a qhuantity of metal oxides to the mixture during the shaking and heatin operation in order to reduce the total car on content of the mix7 ture, the added oxides serving to remove some of the carbon of the mixture as CO and CO2 while the mixture is absorbing the carbon from its surrounding carbonio atmosphere.

In witness whereof, I have hereunto set my hand.

HARRY PETERSSON. 

